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Subject: Re: [PATCH] spmi: hisi-spmi-controller: fix potential memory leak in spmi_controller_probe()
From:   Stephen Boyd <sboyd@kernel.org>
Cc:     linux-kernel@vger.kernel.org, Ma Ke <make_ruc2021@163.com>
To:     Ma Ke <make_ruc2021@163.com>, mchehab+huawei@kernel.org
Date:   Mon, 23 Oct 2023 19:00:20 -0700
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Precedence: bulk

Quoting Ma Ke (2023-09-21 19:52:16)
> spmi_controller_alloc() allocates a memory space for ctrl. When some
> errors occur, ctrl should be handled by spmi_controller_put() and set
> spmi_controller->controller =3D NULL because spmi_controller->controller
> has a dangling pointer to the freed memory. When the failure happens,
> the function returns without calling spmi_controller_put() and setting
> spmi_controller->controller =3D NULL, which will lead to a memory leak.
>=20
> When the failure happens, we can fix it by calling spmi_controller_put()
> and setting spmi_controller->controller =3D NULL in all of the places
> where we call spmi_controller_put().
>=20
> Signed-off-by: Ma Ke <make_ruc2021@163.com>
> ---
>  drivers/spmi/hisi-spmi-controller.c | 1 +
>  1 file changed, 1 insertion(+)
>=20
> diff --git a/drivers/spmi/hisi-spmi-controller.c b/drivers/spmi/hisi-spmi=
-controller.c
> index 9cbd473487cb..5b3cfa7f5056 100644
> --- a/drivers/spmi/hisi-spmi-controller.c
> +++ b/drivers/spmi/hisi-spmi-controller.c
> @@ -321,6 +321,7 @@ static int spmi_controller_probe(struct platform_devi=
ce *pdev)
> =20
>  err_put_controller:
>         spmi_controller_put(ctrl);
> +       spmi_controller->controller =3D NULL;

The controller will most likely be freed after the put call one line
above so this will oops. No thanks.